高精度导航与抗干扰技术
随着全球导航卫星系统（GNSS）技术的飞速发展，其在高精度定位与信号处理领域的应用日益广泛，成为推动现代导航、测绘、智能交通及航空航天等领域进步的重要力量。GNSS以其全球覆盖、高精度、高可靠性和实时性等特点，在多个行业中发挥着不可替代的作用。同时，随着无人驾驶、物联网、智慧城市等新兴技术的兴起，对GNSS高精度定位的需求日益增长，推动了GNSS信号处理技术的不断创新和发展。本专题聚焦于优化导航系统以提升定位精度、稳定性和可靠性，包括超紧组合导航技术的最新进展、高动态环境下的性能提升策略，以及先进传感器的集成与应用。此外，针对日益复杂的电磁环境带来的干扰挑战，专题深入分析了多种先进的抗干扰技术，旨在确保导航信号在复杂环境中的稳定接收。这些研究成果不仅丰富了高精度导航技术的理论体系，也为实际应用场景提供了有效的技术支持和解决方案。
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2023, 45(5):48-59.
DOI: 10.11887/j.cn.202305006
Abstract:
GNSS/INS ultra-tight integrated navigation system has become a research hotspot in the field of integrated navigation due to its high positioning accuracy, excellent dynamic performance and strong anti-jamming ability. The principle of GNSS/INS ultra-tight integration was introduced, and the advantages and features of ultra-tight integration mode relative to other integration modes were compared based on the analysis of the technical principle. The domestic and international research status was introduced, represented by ultra-tight integration under high dynamics and MIMU/GNSS ultra-tight integration. The key technologies such as fault-tolerant control technology, neural network assistance, and multi-sensor assisted ultra-tight integration were summarized, and the prospect of GNSS/INS ultra-tight integration towards low cost, high precision and strong stability was prospected.
GNSS/INS ultra-tight integrated navigation system has become a research hotspot in the field of integrated navigation due to its high positioning accuracy, excellent dynamic performance and strong anti-jamming ability. The principle of GNSS/INS ultra-tight integration was introduced, and the advantages and features of ultra-tight integration mode relative to other integration modes were compared based on the analysis of the technical principle. The domestic and international research status was introduced, represented by ultra-tight integration under high dynamics and MIMU/GNSS ultra-tight integration. The key technologies such as fault-tolerant control technology, neural network assistance, and multi-sensor assisted ultra-tight integration were summarized, and the prospect of GNSS/INS ultra-tight integration towards low cost, high precision and strong stability was prospected.
2023, 45(6):90-99.
DOI: 10.11887/j.cn.202306013
Abstract:
Considering the distributed intermittent interference threat faced by global navigation satellite system receiver, the anti-jamming performance of STAP(space-time adaptive processing) based on sample matrix inversion method was comprehensively and accurately analyzed. Based on the performance analysis model, according to the mismatch of sampling covariance matrix caused by intermittent interferences, the performance of STAP under different conditions was comprehensively analyzed through classification evaluation, combing induction and theoretical derivation. The analysis results show that when the sampling length is less than the scintillation period and the pre-sample method is used, the missed sampling of space-time adaptive processor will occur and the interference suppression performance will decrease sharply, and the frequency of missed sampling is the sum of the scintillation frequencies of each interference. Numerical and simulation analyses verify the results of analysis, and based on this, the optimal design of STAP in the face of distributed intermittent interference is discussed.
Considering the distributed intermittent interference threat faced by global navigation satellite system receiver, the anti-jamming performance of STAP(space-time adaptive processing) based on sample matrix inversion method was comprehensively and accurately analyzed. Based on the performance analysis model, according to the mismatch of sampling covariance matrix caused by intermittent interferences, the performance of STAP under different conditions was comprehensively analyzed through classification evaluation, combing induction and theoretical derivation. The analysis results show that when the sampling length is less than the scintillation period and the pre-sample method is used, the missed sampling of space-time adaptive processor will occur and the interference suppression performance will decrease sharply, and the frequency of missed sampling is the sum of the scintillation frequencies of each interference. Numerical and simulation analyses verify the results of analysis, and based on this, the optimal design of STAP in the face of distributed intermittent interference is discussed.
2023, 45(6):143-149.
DOI: 10.11887/j.cn.202306016
Abstract:
In order to improve the reliability of the single-reference-station based relative positioning solutions over short baselines, the multi-reference-station based relative positioning method was explored. A priori baseline information between the reference stations was integrated into the observable model, thus giving the functional and stochastic models of the multi-reference-station based relative positioning. Based on that, the closed-form formula of the ambiguity dilution of precision for the positioning was derived so that the influence of the number of reference stations on the float ambiguity precision was revealed. Then the impacts of the biases in the a priori baseline information on the integer ambiguity resolution were analyzed theoretically. It show that the integer ambiguity resolution could barely be influenced on the condition that the bias is less than 5 cm. The multi-reference-station based relative positioning method was validated with both the simulated and real data sets. The numerical results show that, increasing the number of reference stations not only improves the single-frequency ambiguity resolution success rate and convergence rate, but also restrains the biases in the a priori baseline information. For example, the ambiguity resolution success rate is still larger than 92% even when the biases of the baseline components attain 4 cm in the field tests. This contribution provides the theoretical foundation for the fast and imprecise calibration between the multiple-reference-station in special scenarios.
In order to improve the reliability of the single-reference-station based relative positioning solutions over short baselines, the multi-reference-station based relative positioning method was explored. A priori baseline information between the reference stations was integrated into the observable model, thus giving the functional and stochastic models of the multi-reference-station based relative positioning. Based on that, the closed-form formula of the ambiguity dilution of precision for the positioning was derived so that the influence of the number of reference stations on the float ambiguity precision was revealed. Then the impacts of the biases in the a priori baseline information on the integer ambiguity resolution were analyzed theoretically. It show that the integer ambiguity resolution could barely be influenced on the condition that the bias is less than 5 cm. The multi-reference-station based relative positioning method was validated with both the simulated and real data sets. The numerical results show that, increasing the number of reference stations not only improves the single-frequency ambiguity resolution success rate and convergence rate, but also restrains the biases in the a priori baseline information. For example, the ambiguity resolution success rate is still larger than 92% even when the biases of the baseline components attain 4 cm in the field tests. This contribution provides the theoretical foundation for the fast and imprecise calibration between the multiple-reference-station in special scenarios.
2023, 45(5):72-77.
DOI: 10.11887/j.cn.202305008
Abstract:
Due to the low transmitting power and large transmission loss, the satellite signal reaching the GNSS receiver is extremely weak, and easy to be interfered. In order to deal with the threat of electromagnetic interference, taking measures at both the system and user level would be a good choice. A model for analyzing the interference suppression capability of anti-jamming receiver with null-steering antenna was established, and the improvement effect of signal power enhancement on the interference suppression performance was quantitatively analyzed. Results show that, the interference mitigation capability of the receiver can be improved by 3～4 dB per 10 dB signal power enhancement. However, from the perspective of improving the receiver′s reception performance(carrier to noise ratio, ranging and positioning accuracy, etc.) under non limiting conditions, when the signal power is increased by 15～20 dB, the reception performance is optimal. The research result can guide the optimization of the signal power enhancement and anti-jamming design of receivers.
Due to the low transmitting power and large transmission loss, the satellite signal reaching the GNSS receiver is extremely weak, and easy to be interfered. In order to deal with the threat of electromagnetic interference, taking measures at both the system and user level would be a good choice. A model for analyzing the interference suppression capability of anti-jamming receiver with null-steering antenna was established, and the improvement effect of signal power enhancement on the interference suppression performance was quantitatively analyzed. Results show that, the interference mitigation capability of the receiver can be improved by 3～4 dB per 10 dB signal power enhancement. However, from the perspective of improving the receiver′s reception performance(carrier to noise ratio, ranging and positioning accuracy, etc.) under non limiting conditions, when the signal power is increased by 15～20 dB, the reception performance is optimal. The research result can guide the optimization of the signal power enhancement and anti-jamming design of receivers.
2023, 45(5):78-86.
DOI: 10.11887/j.cn.202305009
Abstract:
The spinning vehicles are typical applications of GNSS (global navigation satellite system) receivers. When the GNSS carrier spins, the rotation will introduce higher order dynamics making the traditional tracking loop out of lock. Coupling with the INS (inertial navigation system) can effectively compensate the high order dynamic of signal carrier phase. In this case, a design of ultra-tight coupling GNSS tracking loop, which used the solutions of INS to aid the tracking of GNSS signal, was proposed. Besides, the relationship among the aiding rate of INS, the angular rate of spinning vehicle and the error of signal carrier phase was also analyzed. The simulation results show that the proposed tracking loop structure can effectively deal with the problem of signal tracking in the spinning vehicle, and significantly enhance the precision of position compared to the single GNSS navigation results.
The spinning vehicles are typical applications of GNSS (global navigation satellite system) receivers. When the GNSS carrier spins, the rotation will introduce higher order dynamics making the traditional tracking loop out of lock. Coupling with the INS (inertial navigation system) can effectively compensate the high order dynamic of signal carrier phase. In this case, a design of ultra-tight coupling GNSS tracking loop, which used the solutions of INS to aid the tracking of GNSS signal, was proposed. Besides, the relationship among the aiding rate of INS, the angular rate of spinning vehicle and the error of signal carrier phase was also analyzed. The simulation results show that the proposed tracking loop structure can effectively deal with the problem of signal tracking in the spinning vehicle, and significantly enhance the precision of position compared to the single GNSS navigation results.
2023, 45(5):87-94.
DOI: 10.11887/j.cn.202305010
Abstract:
A GNSS multipath channel sparse fitting scheme based on K-medoids clustering was proposed to tackle the problem of a large amount of simulation computation and hardware resource overhead for GNSS channels, which is inconvenient for real-time performance evaluation and practical engineering applications. The equivalent reduced CIR (channel impulse response) parameters were extracted using a sparse fitting method based on K-medoids clustering CIR parameters extraction, and the channel simulation was realized using a sparse tapped-delay-line structure. The proposed method sparsely fits the original GNSS multipath channel model under the constraint of retaining multipath error by employing tapped-delay-line structure filter with fewer taps, which can decrease the complexity of simulation without requiring huge hardware resources. Simulation results show that the proposed scheme is effective by sparse fitting the CIR parameters generated by the reference channel model.
A GNSS multipath channel sparse fitting scheme based on K-medoids clustering was proposed to tackle the problem of a large amount of simulation computation and hardware resource overhead for GNSS channels, which is inconvenient for real-time performance evaluation and practical engineering applications. The equivalent reduced CIR (channel impulse response) parameters were extracted using a sparse fitting method based on K-medoids clustering CIR parameters extraction, and the channel simulation was realized using a sparse tapped-delay-line structure. The proposed method sparsely fits the original GNSS multipath channel model under the constraint of retaining multipath error by employing tapped-delay-line structure filter with fewer taps, which can decrease the complexity of simulation without requiring huge hardware resources. Simulation results show that the proposed scheme is effective by sparse fitting the CIR parameters generated by the reference channel model.
2023, 45(5):105-110.
DOI: 10.11887/j.cn.202305012
Abstract:
A low-complexity method based on pulse blanking for fast frequency-sweep interference mitigation in satellite navigation receivers was proposed. Different from traditional methods based on time-frequency analysis, this method converted the continuous wave interference into pulse interference through a low-pass filter, and then pulse detection and blanking were used to mitigate the interference. The interference was blanked as a pulse when it located in the pass-band of the low-pass filter. Otherwise, it was suppressed as an out-band interference when it located in the stop-band of the low-pass filter. Theoretical analysis and experimental results show that the computation complexity of this method is reduced by an order of magnitude compared with that of traditional method, and it can achieve similar interference suppression performance.
A low-complexity method based on pulse blanking for fast frequency-sweep interference mitigation in satellite navigation receivers was proposed. Different from traditional methods based on time-frequency analysis, this method converted the continuous wave interference into pulse interference through a low-pass filter, and then pulse detection and blanking were used to mitigate the interference. The interference was blanked as a pulse when it located in the pass-band of the low-pass filter. Otherwise, it was suppressed as an out-band interference when it located in the stop-band of the low-pass filter. Theoretical analysis and experimental results show that the computation complexity of this method is reduced by an order of magnitude compared with that of traditional method, and it can achieve similar interference suppression performance.
2023, 45(2):87-94.
DOI: 10.11887/j.cn.202302010
Abstract:
In order to analyze the anti-spoofing performance of the GNSS multi-beam anti-jamming receiver under spoofing interference scenario, a performance metric named deception suppression ratio was put forward. The theoretical formula for the power of the authentic and spoofed signal was deduced considering the anti-jamming receiver using the MVDR (minimum variance distortionless response) algorithm with limited number of snapshots. And the influence of the power of the spoofed signal arriving at the antenna array on the output power of the authentic and spoofed signal was analyzed in detail. The analysis shows that even if the power of the spoofed signal is below the noise level, the multi-beam anti-jamming receiver using the MVDR algorithm can still suppress the spoofing interference. And when the spoofed signal-to-noise ratio is high, the suppression is more effective. The conclusion was verified by simulation and hardware platform test.
In order to analyze the anti-spoofing performance of the GNSS multi-beam anti-jamming receiver under spoofing interference scenario, a performance metric named deception suppression ratio was put forward. The theoretical formula for the power of the authentic and spoofed signal was deduced considering the anti-jamming receiver using the MVDR (minimum variance distortionless response) algorithm with limited number of snapshots. And the influence of the power of the spoofed signal arriving at the antenna array on the output power of the authentic and spoofed signal was analyzed in detail. The analysis shows that even if the power of the spoofed signal is below the noise level, the multi-beam anti-jamming receiver using the MVDR algorithm can still suppress the spoofing interference. And when the spoofed signal-to-noise ratio is high, the suppression is more effective. The conclusion was verified by simulation and hardware platform test.
2023, 45(2):121-130.
DOI: 10.11887/j.cn.202302014
Abstract:
GNSS (global navigation satellite system) vertical time series have the characteristics of non-stationary, non-linear, and noisy. Based on the in-depth study of the Prophet prediction model, and the good predictive effect of Prophet prediction model on trend signals and periodic signals, a “noise reduction-decomposition-prediction” combined prediction method of GNSS vertical time series that introduces EMD (empirical mode decomposition) was proposed. EMD denoising was performed on the original time series, the denoised series were decomposed and predicted, and the predicted signal of each component was reconstructed into the final predicted series. The measured vertical data was used for research, and results show that the average signal-to-noise ratio of the signal after noise reduction is 10.30 dB, and the average energy percentage is 88.75%; using the short-term prediction method, the root-mean-square errors of GNSS vertical time series prediction results are increased by 26.41% and 14.88% on average, respectively; the average percentage errors are increased by 18.92% and 7.91% on average, respectively, and the effectiveness and practicability of the combined forecasting method are verified.
GNSS (global navigation satellite system) vertical time series have the characteristics of non-stationary, non-linear, and noisy. Based on the in-depth study of the Prophet prediction model, and the good predictive effect of Prophet prediction model on trend signals and periodic signals, a “noise reduction-decomposition-prediction” combined prediction method of GNSS vertical time series that introduces EMD (empirical mode decomposition) was proposed. EMD denoising was performed on the original time series, the denoised series were decomposed and predicted, and the predicted signal of each component was reconstructed into the final predicted series. The measured vertical data was used for research, and results show that the average signal-to-noise ratio of the signal after noise reduction is 10.30 dB, and the average energy percentage is 88.75%; using the short-term prediction method, the root-mean-square errors of GNSS vertical time series prediction results are increased by 26.41% and 14.88% on average, respectively; the average percentage errors are increased by 18.92% and 7.91% on average, respectively, and the effectiveness and practicability of the combined forecasting method are verified.
2022, 44(6):109-116.
DOI: 10.11887/j.cn.202206014
Abstract:
In the complex electromagnetic environment of the battlefield, satellite navigation receivers are susceptible to EMI (electromagnetic interference) and cannot be positioned. In response to this phenomenon, a method for evaluating the EMI situation of satellite navigation receivers based on unmanned aerial vehicle′s environmental perception was proposed. When the navigation receiver was not interfered, the characteristic parameters of the EMI and the receiving state of the navigation receiver were used as the input of the prediction. When the receiver tracking loop was lost, the effect threshold was used as the observation target value to establish the XGBoost prediction model. On this basis, the rank of the EMI situation of the navigation receiver was given, and the situation assessment method of the navigation receiver under single-source or dual-source were proposed. Compared with the prediction methods of Gaussian processes for regression and support vector regression, the results show that the XGBoost method has the better prediction accuracy. According to this prediction method, the comprehensive utilization of the technology schemes and the tactical schemes is beneficial to improving the adaptability of unmanned aerial vehicles in complex electromagnetic environments.
In the complex electromagnetic environment of the battlefield, satellite navigation receivers are susceptible to EMI (electromagnetic interference) and cannot be positioned. In response to this phenomenon, a method for evaluating the EMI situation of satellite navigation receivers based on unmanned aerial vehicle′s environmental perception was proposed. When the navigation receiver was not interfered, the characteristic parameters of the EMI and the receiving state of the navigation receiver were used as the input of the prediction. When the receiver tracking loop was lost, the effect threshold was used as the observation target value to establish the XGBoost prediction model. On this basis, the rank of the EMI situation of the navigation receiver was given, and the situation assessment method of the navigation receiver under single-source or dual-source were proposed. Compared with the prediction methods of Gaussian processes for regression and support vector regression, the results show that the XGBoost method has the better prediction accuracy. According to this prediction method, the comprehensive utilization of the technology schemes and the tactical schemes is beneficial to improving the adaptability of unmanned aerial vehicles in complex electromagnetic environments.
2021, 43(4):9-16.
DOI: 10.11887/j.cn.202104002
Abstract:
The power-enhancement technology of GNSS is one of the effective measures to improve the anti-jamming capability of regional satellite navigation signals. How to select power enhancement sub-constellation which has less satellite quantity and better service performance from global constellation is a problem in urgent need to be solved urgently in the construction of modern navigation system. An optimal design method of power-enhanced sub-constellation based on minimum number of satellites was proposed. The design process, mathematical model and optimal solution search strategy were introduced. Availability level, accuracy level and coverage area were defined to evaluate the performance of the power-enhanced sub-constellation. Taking GPS as an example, the optimal design and performance evaluation of power-enhanced sub-constellation was carried out for the application background of covering point target and regional target. The results of simulation show that power enhancement at any target point worldwide requires 12~17 satellites. 18 satellites are needed to achieve continuous coverage to the coastal area of China. And, covering the entire Asia-Pacific region requires full constellation satellite enhancements to meet continuity and accuracy requirements. In this case, the service range of optimal power enhanced sub-constellation can be extended to the whole world.
The power-enhancement technology of GNSS is one of the effective measures to improve the anti-jamming capability of regional satellite navigation signals. How to select power enhancement sub-constellation which has less satellite quantity and better service performance from global constellation is a problem in urgent need to be solved urgently in the construction of modern navigation system. An optimal design method of power-enhanced sub-constellation based on minimum number of satellites was proposed. The design process, mathematical model and optimal solution search strategy were introduced. Availability level, accuracy level and coverage area were defined to evaluate the performance of the power-enhanced sub-constellation. Taking GPS as an example, the optimal design and performance evaluation of power-enhanced sub-constellation was carried out for the application background of covering point target and regional target. The results of simulation show that power enhancement at any target point worldwide requires 12~17 satellites. 18 satellites are needed to achieve continuous coverage to the coastal area of China. And, covering the entire Asia-Pacific region requires full constellation satellite enhancements to meet continuity and accuracy requirements. In this case, the service range of optimal power enhanced sub-constellation can be extended to the whole world.
